Warheads with shaped-charge munition, also known as hollow charge munition, are known to pierce armor and thereby destroy the protected object from within. This capacity of a shaped charge results from the fact that upon detonation there forms an energy-rich jet also known as "thorn" or "spike" which advances at very high speed of several thousand meters per second and is thereby capable of piercing even relatively thick armor walls.
In U.S. Pat. No. 4,368,660 there is described an arrangement which purports to afford protection against the penetrating effect of an exploding shaped charge. According to that proposal there is provided a continuous wall structure having an explosive layer sandwiched between two wall members of an inert material, e.g. a metal, and being so arranged that the axis of an impinging projectile and of the jet formed upon detonation, includes with the surface of the wall structure an acute angle of say 45.degree.. According to the U.S. patent, when a jet of a hollow charge warhead penetrates the upper surface of such a protective arrangement, it initiates the explosive layer and in consequence the walls thereof are thrown apart in opposite directions, both essentially normal to their surfaces. Thus one of the wall members moves in the direction of the protected substrate, while the other moves away and in consequence and due to the acute angle included between the jet and the wall member surfaces, the jet is successively intersected by different portions of the moving wall members with the consequence that the energy and mass of the jet are rapidly consumed whereby the jet is attenuated.
A similar arrangement is disclosed in GB-A-1,581,125 with the sole difference that in accordance with that disclosure the arrangement of the layer of explosive substance may optionally be covered only on one side by a layer of a non-combustible material.
An improved protective armor is disclosed by the present Applicants in their U.S. Pat. No. 4,741,244 and the corresponding EP-B1-O 161,390. This improved protective armor is of the add-on type and consists of a plurality of elements each comprising a cover member having suspended therefrom on the side that faces the substrate at least one explosive insert comprising an explosive layer sandwiched between two metal plates such that when the element is mounted on a substrate the explosive insert remains distant therefrom.
All these prior art reactive armors are based on the mass and energy consuming effects of moving plates and their functioning is conditional on the existence of an acute angle between the jet of an or, coming hollow charge threat and the armored itself, since only in such a case the jet is attenuated by being successively intersected by different portions of the thrown-apart wall members of a hit protective element. Such an acute angle does however not always materialize, typical examples being the roof of an armored land vehicle which is liable to be hit by a shaped charge projectile such as a cluster bomblet arriving normal or near-normal to the surface, i.e. at an angle of about 90.degree. or close thereto, or bazooka plate liable to be hit by anti-armor warheads which may, i.a. arrive normal to such plates. In such an event conventional reactive armors do not perform their function and the jet generated by an oncoming shaped charge warhead is not significantly attenuated, if at all.
It has already been suggested to overcome this problem by mounting reactive armor elements on the roof or on bazooka plate armor askew with respect to the oncoming jet. However, such a solution is only of very little practical value, because the protection afforded in this way is limited to the case of shaped charge warheads arriving at a narrow range of angles at which the reactive armored is effective.